Cryogenic liquids are being used with increasing frequency in industrial processes. One commonly used cryogenic liquid is liquid nitrogen (LN.sub.2) which boils at just above 77.degree. K. at atmospheric pressure. This is about -196.degree. C. Such liquids are difficult to dispose of once their primary cooling effect has been accomplished. If the excess LN.sub.2 is simply dumped into the atmosphere it quickly freezes everything in its vicinity. Atmospheric water is condensed forthwith and quickly forms ice which appears as frost on the venting orifice. Such ice can easily block the vent and prevent further disposal. In any event, the resultant icing is difficult to cope with. Even if the ice is melted by some means the water thereby produced must be handled. One approach is to convert all of the LN.sub.2 to gas, warm it, and vent it into the atmosphere. Alternatively, the gas can be recycled back into the system.